July 23, 2014

Happy 15th Anniversary Chandra!

NASA's Space Shuttle Columbia carried the Chandra X-ray Observatory into space 15 years ago, deploying it on July 23, 1999. Chandra, along with the other "Great Observatories" like Hubble and Spitzer, has helped to revolutionize the way we view the Universe using an unprecedented X-ray vision.

"Chandra changed the way we do astronomy. It showed that precision observation of the X-rays from cosmic sources is critical to understanding what is going on," said Paul Hertz, NASA's Astrophysics Division director in Washington, in a NASA statement. "We're fortunate we've had 15 years – so far – to use Chandra to advance our understanding of stars, galaxies, black holes, dark energy, and the origin of the elements necessary for life."

To celebrate Chandra's "birthday," NASA has released four newly processed images of supernova remnants. These images display Chandra's unique ability to use X-rays to explore high-energy processes in the universe. The four remnants are Tycho, G292.0+1.8, The Crab Nebula, and 3C58.

The Tycho and G292.0+1.8 images reveal Chandra's ability to trace the expanding debris field created by an exploding star, and the associated shock waves the explosion causes to push through space at millions of miles per hour. The Crab Nebula and 3C58 images demonstrate how extremely dense, rapidly rotating neutron stars — produced when a massive star explodes — are able to create clouds of high-energy particles. These clouds glow brightly in the X-ray spectrum and are light-years wide.

Tycho — named for the Danish astronomer Tycho Brahe, who first observed the supernova four hundred years ago — is a bright source of X-rays. When the star exploded, it created two shockwaves: one that moves outward from the remnant into the surrounding interstellar gas, and a second that moves back in towards the star. In the image, the dynamics of this explosion are rendered in unparalleled detail. The blue represents the expanding outward shell of extremely high-energy electrons, while the red and green represents the expanding debris that has been heated to millions of degrees by the reverse shockwave. Astronomers believe that the Chandra data presents evidence that the Tycho shockwaves may be the source for some of the cosmic rays that constantly bombard the Earth.

G292.0+1.8 is one of only three supernova remnants in the Milky Way known to contain large quantities of oxygen. Astronomers are intrigued by oxygen-rich supernovas because they are a primary source of heavy elements that are necessary for the creation of planets and people. The new image from Chandra shows these elements as colors: yellow and orange for oxygen, green for magnesium, and blue for silicon and sulfur. The rapidly expanding debris field is comprised of these elements that were formed in the star before it exploded.

The Crab Nebula was discovered by astronomers around the world in 1054 AD. An extremely dense, rapidly rotating neutron star, left behind by the main explosion, is at the center of the nebula. This type of star is known as a pulsar, which creates a virtual expanding blizzard of high-energy particles. The X-rays from this cloud produce the nebula captured by Chandra. The image provides detail on the types of X-rays emitted: high-energy are blue, medium energy are green and low-energy are red.

3C58 is the remnant of a supernova that Chinese and Japanese astronomers observed in 1181 AD. The center of the remnant is visible in the Chandra image, which reveals a rapidly spinning neutron star surrounded by a torus — a thick ring of X-ray emissions. X-ray jets also stream away from the pulsar to the left and right, extending trillions of miles on either side, creating the loops and swirls seen in the image. These features provide evidence that supernova remnants such as 3C58 are capable of not only producing swarms of high-energy particles, but also powerful magnetic fields. The image shows the different levels of X-rays with red representing low-energy, green representing medium energy, and blue representing high-energy.